Rationale: Breathlessness greatly contributes to exercise limitation in patients with COPD. In patients with COPD, as exercise intensity increases, respiratory rate increases, and tidal volume is unchanged or decreases, thus contributing to a further sensation of dyspnea. Whether modulating the breathing pattern during exercise could reduce dyspnea in these patients is unknown.

Objective: To determine whether breathing patterns are affected by a computerized breathing retraining program. To determine whether a breathing retraining and exercise program reduces dyspnea in patients with COPD.

Methodology: The effect of 3 pulmonary rehabilitation training programs on breathing patterns and dyspnea were evaluated in 64 patients with COPD (FEV1 1.4+/-0.6 L). Patients were randomized to 1 of 3 groups: computerized ventilation-feedback plus exercise (n = 22), exercise only (n = 20), and ventilation-feedback training only (n = 22). Ventilation feedback consists of a pneumotachometer and prototype computer program that provides the subject with visual and auditory feedback of his/her success in satisfying the specified "goal breathing pattern" during exercise. All testing is completed without ventilation-feedback.

Results: After 12 weeks of training, respiratory parameters were measured at an isotime corresponding to peak exercise time during the baseline test. Expiratory time increased by 36% (P < .001) in the E+VF group and 34% (P < .01) in the VF feedback only group; the corresponding increase expiratory time in the E-only group was 11% (P = .03). Respiratory rate decreased by 24% (P < .001) in the E+VF group, 13% (P = .01) in the VF-only group and 7% (P = .05) in the exercise-only group. Tidal volume was unchanged in all 3 groups. The reduction in perceived dyspnea at isotime was similar across the 3 groups. Although isotime dyspnea reduction was similar across the 3 groups, fewer patients in the E+VF group stopped exercise due to dyspnea after training than in the other 2 groups.

Conclusion: Subjects randomized to the E+VF- and VF-only groups were able to alter their breathing patterns post-exercise training. After training, fewer patients in the E+VF group stopped exercise due to dyspnea than in the other 2 training groups.